The Impact of Individual Teachers on Student Achievement: Evidence from Panel Data

Teacher quality is widely believed to be important for education, despite little evidence that teachers' credentials matter for student achievement. To accurately measure variation in achievement due to teachers' characteristics-both observable and unobservable-it is essential to identify teacher fixed effects. Unlike previous studies, I use panel data to estimate teacher fixed effects while controlling for fixed student characteristics and classroom specific variables. I find large and statistically significant differences among teachers: a one standard deviation increase in teacher quality raises reading and math test scores by approximately .20 and .24 standard deviations, respectively, on a nationally standardized scale. In addition, teaching experience has statistically significant positive effects on reading test scores, controlling for fixed teacher quality.teachers

There Goes the Neighborhood? Estimates of the Impact of Crime Risk on Property Values From Megan's Laws

We combine data from the housing market with data from the North Carolina Sex Offender Registry to estimate how individuals value living in close proximity to a convicted criminal. We use the exact location of sex offenders to exploit variation in the threat of crime within small homogenous groupings of homes, and we use the timing of sex offenders' arrivals to control for baseline property values in the area. We find statistically and economically significant negative effects of sex offenders' locations that are extremely localized. Houses within a one-tenth mile area around the home of a sex offender fall by 4 percent on average (about $5,500). We also find evidence that the effect varies with distance within this range -- houses next to an offender sell for about 12 percent less while those a tenth of a mile away or more show no decline. We combine our willingness-to-pay estimates with data on sexual crimes against neighbors to estimate the costs to victims of sexual offenses. We estimate costs of over$1 million per victim -- far in excess of estimates taken from the criminal justice literature. However, we cannot reject the alternative hypotheses that individuals overestimate the risk posed by offenders or view living near an offender as having costs exclusive of crime risk.

The Long-Term Impacts of Teachers: Teacher Value-Added and Student Outcomes in Adulthood

Are teachers’ impacts on students’ test scores (“value-added”) a good measure of their quality? This question has sparked debate largely because of disagreement about (1) whether value-added (VA) provides unbiased estimates of teachers’ impacts on student achievement and (2) whether high-VA teachers improve students’ long-term outcomes. We address these two issues by analyzing school district data from grades 3-8 for 2.5 million children linked to tax records on parent characteristics and adult outcomes. We find no evidence of bias in VA estimates using previously unobserved parent characteristics and a quasi-experimental research design based on changes in teaching staff. Students assigned to high-VA teachers are more likely to attend college, attend higher- ranked colleges, earn higher salaries, live in higher SES neighborhoods, and save more for retirement. They are also less likely to have children as teenagers. Teachers have large impacts in all grades from 4 to 8. On average, a one standard deviation improvement in teacher VA in a single grade raises earnings by about 1% at age 28. Replacing a teacher whose VA is in the bottom 5% with an average teacher would increase the present value of students’ lifetime income by more than $250,000 for the average class- room in our sample. We conclude that good teachers create substantial economic value and that test score impacts are helpful in identifying such teachers.

Do Sex Offender Registration and Notification Laws Affect Criminal Behavior?

In recent decades, sex offenders have been the targets of some of the most far-reaching and novel crime legislation in the U.S. Two key innovations have been registration and notification laws which, respectively, require that convicted sex offenders provide valid contact information to law enforcement authorities, and that information on sex offenders be made public. Using detailed information on the timing and scope of changes in state law, we study how registration and notification affect the frequency of sex offenses and the incidence of offenses across victims, and check for any change in police response to reported crimes. We find evidence that registration reduces the frequency of sex offenses by providing law enforcement with information on local sex offenders. As we predict from a simple model of criminal behavior, this decrease in crime is concentrated among "local" victims (e.g., friends, acquaintances, neighbors), while there is little evidence of a decrease in crimes against strangers. We also find evidence that community notification deters crime, but in a way unanticipated by legislators. Our results correspond with a model in which community notification deters first-time sex offenses, but increases recidivism by registered offenders due to a change in the relative utility of legal and illegal behavior. This finding is consistent with work by criminologists suggesting that notification may increase recidivism by imposing social and financial costs on registered sex offenders and making non-criminal activity relatively less attractive. We regard this latter finding as potentially important, given that the purpose of community notification is to reduce recidivism.

What Does Certification Tell Us About Teacher Effectiveness? Evidence from New York City

We use six years of data on student test performance to evaluate the effectiveness of certified, uncertified, and alternatively certified teachers in the New York City public schools. On average, the certification status of a teacher has at most small impacts on student test performance. However, among those with the same certification status, there are large and persistent differences in teacher effectiveness. This evidence suggests that classroom performance during the first two years, rather than certification status, is a more reliable indicator of a teacher's future effectiveness. We also evaluate turnover among teachers with different certification status, and the impact on student achievement of hiring teachers with predictably high turnover. Given relatively modest estimates of experience differentials, even high turnover groups (such as Teach for America participants) would have to be only slightly more effective in their first year to offset the negative effects of their high exit rates.

Do Sex Offender Registration and Notification Laws Affect Criminal Behavior?

Sex offenders have become the targets of some of the most far-reaching and novel crime legislation in the U.S. Two key innovations in recent decades have been registration and notification laws which, respectively, require that convicted sex offenders provide valid contact information to law enforcement authorities, and that information about sex offenders be made public. Using the evolution of state law during the 1990s and 2000s, we study how registration and notification affect the frequency of reported sex offenses and the incidence of such offenses across victims. We find evidence that registration reduces the frequency of sex offenses by providing law enforcement with information on local sex offenders. As we predict using a simple model of criminal behavior, this decrease in crime is concentrated among “local” victims (e.g., friends, acquaintances, neighbors) with no evidence of less crime occurring against strangers. We also find evidence that notification has reduced crime, but not, as legislators anticipated, by disrupting the criminal conduct of convicted sex offenders. Our results instead suggest that notification deters nonregistered sex offenders, and may, in fact, increase recidivism among registered offenders by reducing the relative attractiveness of a crime-free life. This finding is consistent with work by criminologists showing that notification imposes social and financial costs on registered sex offenders, perhaps offsetting the relative benefits of forgoing criminal activity. We regard this latter finding as important, given that the purpose of notification is to reduce recidivism

Searching for Effective Teachers with Imperfect Information

Over the past four decades, empirical researchers -- many of them economists -- have accumulated an impressive amount of evidence on teachers. In this paper, we ask what the existing evidence implies for how school leaders might recruit, evaluate, and retain teachers. We begin by summarizing the evidence on five key points, referring to existing work and to evidence we have accumulated from our research with the nation\u27s two largest school districts: Los Angeles and New York City. First, teachers display considerable heterogeneity in their effects on student achievement gains. Second, estimates of teacher effectiveness based on student achievement data are noisy measures. Third, teachers\u27 effectiveness rises rapidly in the first year or two of their teaching careers but then quickly levels out. Fourth, the primary cost of teacher turnover is not the direct cost of hiring and firing, but rather is the loss to students who will be taught by a novice teacher rather than one with several years of experience. Fifth, it is difficult to identify at the time of hire those teachers who will prove more effective. As a result, better teachers can only be identified after some evidence on their actual job performance has accumulated. We then explore what these facts imply for how principals and school districts should act, using a simple model in which schools must search for teachers using noisy signals of teacher effectiveness. The implications of our analysis are strikingly different from current practice. Rather than screening at the time of hire, the evidence on heterogeneity of teacher performance suggests a better strategy would be identifying large differences between teachers by observing the first few years of teaching performance and retaining only the highest-performing teachers

Do Sex Offender Registration and Notification Laws Affect Criminal Behavior?

Sex offenders have become the targets of some of the most far-reaching and novel crime legislation in the U.S. Two key innovations in recent decades have been registration and notification laws which, respectively, require that convicted sex offenders provide valid contact information to law enforcement authorities, and that information about sex offenders be made public. Using the evolution of state law during the 1990s and 2000s, we study how registration and notification affect the frequency of reported sex offenses and the incidence of such offenses across victims. We find evidence that registration reduces the frequency of sex offenses by providing law enforcement with information on local sex offenders. As we predict using a simple model of criminal behavior, this decrease in crime is concentrated among “local” victims (e.g., friends, acquaintances, neighbors) with no evidence of less crime occurring against strangers. We also find evidence that notification has reduced crime, but not, as legislators anticipated, by disrupting the criminal conduct of convicted sex offenders. Our results instead suggest that notification deters nonregistered sex offenders, and may, in fact, increase recidivism among registered offenders by reducing the relative attractiveness of a crime-free life. This finding is consistent with work by criminologists showing that notification imposes social and financial costs on registered sex offenders, perhaps offsetting the relative benefits of forgoing criminal activity. We regard this latter finding as important, given that the purpose of notification is to reduce recidivism

Stuck in the Middle: Impacts of Grade Configuration in Public Schools

We examine the implications of separating students of different grade levels across schools for the purposes of educational production. Specifically, we find that moving students from elementary to middle school in 6th or 7th grade causes significant drops in academic achievement. These effects are large (about 0.15 standard deviations), present for both math and English, and persist through grade 8, the last year for which we have achievement data. The effects are similar for boys and girls, but stronger for student s with low levels of initial achievement. We instrument for middle school attendance using the grade range of the school students attended in grade 3, and employ specifications that control for student fixed effects. This leaves only one potential source of bias—correlation between grade range of a student’s grade 3 school and unobservable characteristics that cause decreases in achievement precisely when students are due to switch schools—which we view as highly unlikely. We find little evidence that placing public school students into middle schools during adolescence is cost-effective

Do Sex Offender Registration and Notification Laws Affect Criminal Behavior?

In recent decades, sex offenders have been the targets of some of the most far-reaching and novel crime legislation in the U.S. Two key innovations have been registration and notification laws which, respectively, require that convicted sex offenders provide valid contact information to law enforcement authorities, and that information on sex offenders be made public. Using detailed information on the timing and scope of changes in state law, we study how registration and notification affect the frequency of sex offenses and the incidence of offenses across victims, and check for any change in police response to reported crimes. We find evidence that registration reduces the frequency of sex offenses by providing law enforcement with information on local sex offenders. As we predict from a simple model of criminal behavior, this decrease in crime is concentrated among “local” victims (e.g., friends, acquaintances, neighbors), while there is little evidence of a decrease in crimes against strangers. We also find evidence that community notification deters crime, but in a way unanticipated by legislators. Our results correspond with a model in which community notification deters first-time sex offenses, but increases recidivism by registered offenders due to a change in the relative utility of legal and illegal behavior. This finding is consistent with work by criminologists suggesting that notification may increase recidivism by imposing social and financial costs on registered sex offenders and making non-criminal activity relatively less attractive. We regard this latter finding as potentially important, given that the purpose of community notification is to reduce recidivism